Two and a half days after my RSS rant, I found feeds on the PCUSA website. They're just buried really deep and a bit of a pain to subscribe to. Most websites just includes a link to the feed. That way, you can click on it to view the feed or right-click and copy its location and paste it into your viewer. The PCUSA site links to a page that tells you all about RSS (it does a good job) and it buries the links to the feeds all the way at the bottom. It does have an "add feeds" link at the top of the page, but that only sends you to the bottom of the page where the links actually are.
My other big disappointment is that they don't have any mention of it on their home page which means it's not a priority and that's probably a big reason why I couldn't find it in the first place. This is also a big deal because most modern browsers will display this icon 
in the header to tell you a site has a feed. You can then use that icon to subscribe to the feed. It's the quickest and easiest way. Firefox 2 will even automatically add the subscription to my Google Reader account for me.
I do have to eat some crow here for two reasons. First, this site doesn't have RSS on it's home page. I'm a bit disappointed Community Server doesn't do this, but you don't get everything you want when you base your site on free software and I'm generally quite pleased with it. Secondly, I just Googled PCUSA rss and found results quickly. While I use Google all the time to find things, that's not how I find RSS when I know a site. Because Christian mission hasn't entirely embraced technology, it looks like I have to use different techniques to find what I'm looking for.